1997 Fiscal Year Final Research Report Summary
RESEARCH ON CASCADE OVELAPPING EFFECTS BY COMBINED IRRADIATION EXPERIMENTS
| Project/Area Number |
08458118
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
エネルギー学一般・原子力学
|
|---|
| Research Institution | THE UNIVERSITY of TOKYO |
|---|
Principal Investigator |
SEKIMURA Naoto THE UNIVERSITY OF TOKYO,SCHOOL OF ENGINEERING,ASSOCIATE PROFESSOR, 工学系研究科, 助教授 (10183055)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
IWATA Shuichi THE UNIVERSITY OF TOKYO,RESEARCH INTO ARTIFACT CENTER,PROFESSOR, 人工物工学研究センター, 教授 (50124665)
ISHINO Shiori TOKAI UNIVERSITY,FACULTY OF ENGINEERING,PROFESSOR, 工学部, 教授 (70010733)
KAWANISHI Hiroshi The UNIVERSITY OF TOKYO,SCHOOL OF ENGINEERING,RESEARCH ASSOCIATE, 工学系研究科, 助手 (40010970)
IWAI Takeo THE UNIVERSITY OF TOKYO,RESEARCH CENTER FOR NUCLEAR SCI., RESEARCH ASSOCIATE, 原子力研究総合センター, 助手 (30272529)
|
|---|
| Project Period (FY) |
1996 – 1997
|
| Keywords | COMBINED IRRADIATION / MATERIALS MODELING / NEUTRON IRRADIATION / ION IRRADIATION / CASCADE DAMAGE / DEFECT CLUSTERS |
|---|
| Research Abstract |
Combined irradiation experiments are designed to obtain required information for modeling of materials behavior. Combined irradiation experiments contains neutron irradiation of irradiated materials under different conditions with neutrons, ions or electron, and also charged particle irradiation of irradiated materials with neutrons.
In thin foils of gold irradiated with fast neutrons, density of vacancy clusters increases linearly with dose and then shows super-linear increase. Cascade damage can be divided into several sub-cascades, and observed clusters form group of clusters. Distributions of number of clusters in a group is found to increase with dose. This can be attributed to the overlapping of cascades which cause the formation of new small defect clusters near the existing group of cluster. This phenomena is also found to be dependent on the primary knock-on atom (PKA) energy, comparing fission and fusion neutron irradiation results. To confirm this PKA energy dependence, self-ions with several energies are irradiated to thin foils of gold followed by fast neutron irradiation. From these combined irradiation experiments, following new results are obtained ; 1) invisible defect clusters are created by cascade damage in addition to visible defect cluster. 2) Invisible defect clusters are converted to visible defect clusters by overlap of cascades and this critical interaction length is estimated as a function of PKA energy. 3) The efficiency of formation of invisible clusters and their conversion to visible clusters is also quantitatively estimated.
|
